Remote Neovim can't open a new display nor paste into c

[drjaska]

I have xclip and isomorphic_copy on both PCs and cssh open, I have set below snippet in my Neovim's init.lua, copied from the README

vim.cmd([[
  if has('nvim')
    " use unnamedplus only! or else will double set
    set clipboard=unnamedplus
    if getenv('DISPLAY') == v:null
      exe setenv('DISPLAY', 'FAKE')
    endif
  else
    autocmd TextYankPost * call system("c", getreg('"'))
  endif
]])

:checkhealth:

## Clipboard (optional)
  - OK: Clipboard tool found: xclip

When I try to execute "+Y over SSH I get: clipboard: error invoking xclip: Error: Can't...display: FAKE Error: Can't open display: FAKE

If I try cat testfile | xclip -selection clipboard I do get clipboard content from remote (with #5 error prints) but without ISOCP_USE_FILE=1 remote doesn't retain anything.

⚠️  No system clipboard detected ⚠️

export ISOCP_USE_FILE=1 to use temp file

Am I lacking a TTY clipboard service, lacking a tool to open arbitrary X sessions or is there some other issue?

[drjaska]

ssh -X does work around these errors.